
<template>
    <div class="person">
      <h2>sum:{{sum}}</h2>
      <button @click="changeSum">sum+1</button>

    </div>
  </template>
  
  <script lang="ts" setup>
  import {ref} from 'vue'
  let sum = ref(0)

  function changeSum(){
    sum.value += 1  
  }

  </script>